Method for manufacturing metal parts with split ends joined

ABSTRACT

A method for manufacturing metal parts with split ends joined. An end of a metal plate or solid metal rod is split. The length of the incision is adjusted and a smooth split face is formed. A metal plate is secured by pinching both sides with a clamping device, or a solid metal rod is pinched on opposite portions on the periphery with a clamping device. The plate/rod is split longitudinally by slitting or cleaving the plate/rod by pressing a slitting or cleaving punch against the face of one end of the plate/rod. The splitting is advanced by repeating the operation of pressing the punch against the cleft of the splitting. In each splitting operation, the position of the clamping device is moved in advance of the next pressing by a stroke corresponding to the distance from one end of the plate/rod, to the distal end of a split-desired portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of pending U.S. patent application Ser. No.15/180,546, filed Jun. 13, 2016, which is a divisional of U.S. patentapplication Ser. No. 14/375,948, filed Jul. 31, 2014, now U.S. Pat. No.9,855,667, which is a national stage entry of International PatentApplication Serial No. PCT/JP2012/080802, filed Nov. 21, 2012, whichclaims priority to Japanese Patent Application No. 2012-146254, filedJun. 29, 2012, the entirety of which applications and patent areincorporated by reference herein.

FIELD OF THE DISCLOSURE

The present invention relates to a method for manufacturing metal partswith split ends joined, the metal parts being obtained by splitting anend part of a metal plate having any of a rectangular, polygonal, orelliptical shape, or an end part of a metal rod having a cross-sectionof any of a circular, elliptical, rectangular, or polygonal shape, inthe longitudinal direction with respect to the metal plate or the metalrod, wherein the method permits free-adjustment of the length ofincision in the split ends and provides smooth and even split faces.

BACKGROUND OF THE DISCLOSURE

Positive displacement pumps such as three screw pumps, are well-known.In positive displacement screw pumps, pressure is developed from theinlet or suction port of the pump to the outlet or discharge port instage-to-stage increments. Properly applied, a rotary three-screw pumpcan be used to pump a broad range of fluids, from high-viscosity liquidsto relatively light fuels or water/oil emulsions.

Until now in the field of sheet metal V-pulleys and sheet metal brakeshoes, a manufacturing method such that a rotating slitting roller or arotating cleaving roller is pressed against the outer peripheral portionof a circular metal material to split such portion into two parts isknown (see Patent literatures 1 to 5). This method has advantages ofexcellent dimensional accuracy and reliability together with reducedmanufacturing cost compared to a conventional method such as welding,press-forming, or casting, because the method can split accurately andeasily a blank at a desired position in the thickness direction of theouter periphery thereof.

Further, Patent literatures 6 and 7 have disclosed a forming method inthe manufacture of V-pulleys. In the disclosed method, one of two lugs(or formed portions of a guide), which are to be formed on the bothsides of outer periphery of a cylindrical body bulging in the axialdirection for prevention of V-belt slip-off, is formed by cleaving usinga cylindrical-shaped cleaving punch.

Patent literature 8 has proposed a forming method in the manufacture ofdrum brakes. In the proposed method, the circumferential peripheralportion of a bottomed cylindrical metal body is cut by a cutting die inorder to form a dust cover portion integrally with a flange portion andthen the cut portion is drawn by a press die to form a cylindricalportion that works as the integrated dust cover.

Further, a method of end splitting for a workpiece of relatively softmaterial, different from a metal plate or a metal rod, has beendisclosed in Patent literature 9. This method is to cut a divider stripof soft synthetic resin into longitudinal halves by pulling the dividerstrip with a cutter blade applied on the cross-section of the endthereof.

-   {Patent literature 1} Japanese patent application laid-open No.    1986-129241-   {Patent literature 2} Japanese patent No. 3686903-   {Patent literature 3} Japanese patent application laid-open No.    1994-210361-   {Patent literature 4} Japanese patent No. 2520095-   {Patent literature 5} Japanese patent application laid-open No.    1996-267162-   {Patent literature 6} International publication No. WO 00/54905-   {Patent literature 7} Japanese patent application laid-open No.    1996-300082-   {Patent literature 8} Japanese patent application laid-open No.    2002-45940-   {Patent literature 9} Japanese utility model application laid-open    No. 1988-78639

SUMMARY OF THE DISCLOSURE

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended asan aid in determining the scope of the claimed subject matter.

In contrast, if there is a method that is applicable to the longitudinalsplitting of the end part of a metal plate having any of a rectangular,polygonal, or elliptical shape, or a metal rod having a cross-section ofany of a circular, elliptical, rectangular, or polygonal shape, i.e.,not a circular metal material like a V-pulley or a brake shoe mentionedabove, various applications of such method will be promising. Forexample, if a metal plate or a metal rod having a style of Figure-Yshape, Figure-T shape, or Figure-L shape can be manufactured simply bysplitting-forming and mold-press forming without undergoing a process ofwelding, fusing, or gluing, a large cost-cut in manufacturing will beachieved through reduction in use quantity of material and manufacturingman-hours. Further, an effect of significant improvement in thereliability of the bonding or joining, which has been a problem in theconventional methods such as welding, fusing, or gluing, becomesachievable.

In addition, when welding or fusing method is used in the bondingbetween plates of dissimilar metals, it is hard to obtain a bonding withadequate quality due to difference in physical properties of both metalssuch as electrical conductivity, thermal conductivity, or melting point.Therefore, even though adequate bonding quality be obtained, thestability thereof is not assured because such methods create verybrittle intermetallic compounds at the bonding interface. In the casethat the bonding between two dissimilar metal plates is made by gluing,a low bonding strength is unavoidable due to difference in linearexpansion coefficient between the two; thus, ensuring reliable bondinghas been a major issue. In contrast to this, the strength andreliability of bonding or joining will be largely improved whenperformed in a manner: splitting the end part of a first metal plate, ora first metal rod, sandwiching a second metal plate of dissimilarmaterial between the end split portions of the first metal plate, or thefirst metal rod, to form a three-layer build-up, and then performbonding or joining with a conventional method.

Further, if free-adjustment of the split length (or depth) at the splitportion on the end of a metal plate or a metal rod becomes practicable,flexibility in the shaping process will increase. Consequently, theapplicability of the invented method to the fields of precision parts,hard-to-process parts, and parts that require high reliability anddurability will significantly expand.

However, the splitting methods described in Patent literatures 1 to 5listed above are to be applied to metallic workpieces of circular ordisk-like metal plates. In those methods, a splitting roller or acleaving roller is pressed against the peripheral portion of the metalplate to split the portion with the roller rotated in synchronizationwith the rotation of the circular or disk-like metal plates. Therefore,the methods are not applicable to metal plates having any of arectangular, polygonal, or elliptical shape, or to a metal rod having across-section of any of a circular, elliptical, rectangular, orpolygonal shape. The rotating of the metallic workpiece and the rollerproduces uniform splitting to a specified length (or depth) only whenapplied to a metallic workpiece that is a metal plate having a circularor a disk-like shape. In the case of a metal plate or a metal rod havinga style other than circular or disk-like shape however, it is notpossible to obtain such an effect because a uniform rotation of theworking face is impossible to attain.

In addition, Patent literatures 6 and 7 listed above describe a cleavingmachining using a cylindrical-shaped cleaving punch but that cleavingmachining intends to form a small lug (or the formed portion of a guide)for prevention of V-belt slip-off. Thus, the literatures do not describenor suggest a method for splitting further the lug (or the formedportion of a guide) to a freely-determined length of incision. Thismeans that the art described in the literatures has not recognized anactive use of the split metal portion as a constituent of a metallicpart.

The method described in Patent literature 8 listed above cuts thecircumferential peripheral portion of a bottomed cylindrical metal bodyusing a cup die. In this processing, the bottomed cylindrical bodyshould be rotated so as to obtain an even split face. Therefore, thismethod is not applicable to metal plates or metal rods having any of arectangular, polygonal, or elliptical shape, similarly in theabove-stated case.

The invention described in Patent literature 9 listed above is a methodfor cutting the cross-section of a divider strip of relatively softsynthetic resin to split the divider strip; the defined art is differentone from forming by the splitting, slitting, or cleaving of a metal rod.This means that that invention has not recognized any technical matterthat could arise as a problem in splitting a cross-sectional end of ametallic material. Thus, that art cannot be applicable to the endsplitting of a metal plate or metal rod, as the art is.

As stated above, there has been strong desire for a method forsplitting, similarly in the circular or disk-like shaped metal plate, anend part of a metal plate having any of a rectangular, polygonal, orelliptical shape, or an end part of a metal rod having any of across-section of a circular, elliptical, rectangular, or polygonalshape, in the longitudinal direction with respect to the metal plate orthe metal rod. In spite of such desire, few ideas have been proposeduntil now that permits free-adjustment of the length of incision in thesplit portion and providing a smooth split faces.

The present invention is made to solve such problems and an object ofthe invention is to provide a method for splitting an end part of ametal plate having any of a rectangular, polygonal, or elliptical shape,or an end part of a metal rod having a cross-section of any of acircular, elliptical, rectangular, or polygonal shape, in thelongitudinal direction with respect to the metal plate or the metal rod,wherein the method permits free-adjustment of the length of incision inthe split portion and provides a smooth split surfaces.

Further, the present invention aims to provide a metal parts having ahigh-function and a high-value added feature manufactured by the methodfor splitting an end part of metal plate or metal rod stated above, andto provide a high strength and reliability bonding method of metalparts.

The inventor of the present invention has reached this invention basedon a finding that the above-stated problems can be solved by repeatingpress-splitting using a slitting punch or a cleaving punch consecutivelymany times, not only one time, in splitting an end part of a metal platehaving any of a rectangular, polygonal, or elliptical shape, or an endpart of a metal rod having any of a cross-section of a circular,elliptical, rectangular, or polygonal shape, and by moving the positionof a clamping device for pinching the metal plate or the metal rod ineach time of the press-splitting operation so that the length of theincision in the splitting can be freely adjusted to the optimizedcondition.

That is, the configuration of the present invention is as follows.

(1) The present invention is to provide a method for manufacturing metalparts with split ends joined, wherein the method comprises;

securing a metal plate having any of a rectangular, polygonal, orelliptical shape by pinching both sides thereof with a clamping device,or securing a solid metal rod having a cross-section of any of acircular, elliptical, rectangular, or polygonal shape by pinching atleast two opposite-facing portions on the periphery thereof with aclamping device;

advancing splitting by pressing a slitting punch or a cleaving punchagainst a cleft of a split for repeatedly two or more times until asplit length reaches a specified extent;

inserting another metal plate between the split ends of the metal plateor the metal rod split; and

joining both the metals mutually and permanently by a method includingany of pressing perpendicular to a splitting direction of the metalplate or the solid metal rod, welding, fusing, bolting, riveting, orgluing,

wherein, in advance of each time of each subsequent splitting operationof the two or more times,

a position of at least one side of the clamping device that pinches bothsides of the metal plate in a prior operation of securing or thatpinches at least two opposite-facing portions on a periphery of thesolid metal rod in the prior operation of securing, is moved along themetal plate or the solid metal rod in advance by a stroke correspondingto a distance from a position of the cleft of the split toward a distalend of a split desired position, followed by securing of the metal plateby pinching both sides thereof with the clamping device, or by securingof the solid metal rod by pinching at least two opposite-facing portionson the periphery thereof with the clamping device,

wherein, in each interval between splitting operations of the two ormore times, pressing of the splitting punch or the cleaving punch issuspended,

wherein, on both sides in the case of the splitting punch or on one sidein the case of the cleaving punch, a cutting edge is given a taperingshape having at least two taper portions of different angles orcurvatures so that the taper portion of the side closer to a tip end ofthe cutting edge has a smaller inclination angle when measuredcounterclockwise from a horizontal axis extending perpendicular relativeto a longitudinal axis passing through the cutting edge of the splittingpunch or the cleaving punch, or a smaller curvature than that of thetaper on the side apart from the tip end of the cutting edge.

(2) The present invention is to provide a method for manufacturing metalparts with split ends joined, wherein the method comprises;

determining a desired length of cutting plane in the thickness directionof a metal plate having any of a rectangular, polygonal, or ellipticalshape, or in the diameter direction of a solid metal rod having across-section of any of a circular, elliptical, rectangular, orpolygonal shape;

applying a slitting punch or a cleaving punch on the cross-section ofthe split-desired end of the metal plate, or the metal rod, on aboundary created by the cutting plane;

securing the metal plate by pinching both sides of a split-desiredportion thereof with a clamping device, or securing the metal rod bypinching at least two opposite-facing portions on the periphery of asplit-desired portion thereof with a clamping device;

advancing splitting by pressing a slitting punch or a cleaving punchagainst a cleft of a split for repeatedly two or more times until asplit length reaches a specified extent;

inserting another metal plate between the split ends of the metal plateor the metal rod split; and

joining both the metals mutually and permanently by a method includingany of pressing perpendicular to a splitting direction of the metalplate or the solid metal rod, welding, fusing, bolting, riveting, orgluing,

wherein, in advance of each time of each subsequent splitting operationof the two or more times,

a position of at least one side of the clamping device that pinches bothsides of the metal plate in a prior operation of securing or thatpinches at least two opposite-facing portions on a periphery of thesolid metal rod in the prior operation of securing, is moved along themetal plate or the solid metal rod in advance by a stroke correspondingto a distance from a position of the cleft of the split toward a distalend of a split desired position, followed by securing of the metal plateby pinching both sides thereof with the clamping device, or by securingof the solid metal rod by pinching at least two opposite-facing portionson the periphery thereof with the clamping device; and

thereby the metal plate, or the metal rod, is partially split in alongitudinal direction along the cutting plane,

wherein, in each interval between splitting operations of the two ormore times, pressing of the splitting punch or the cleaving punch issuspended,

wherein, on both sides in the case of the splitting punch or on one sidein the case of the cleaving punch, a cutting edge is given a taperingshape having at least two taper portions of different angles orcurvatures so that the taper portion of the side closer to a tip end ofthe cutting edge has a smaller inclination angle when measuredcounterclockwise from a horizontal axis extending perpendicular relativeto a longitudinal axis passing through the cutting edge of the splittingpunch or the cleaving punch, or a smaller curvature than that of thetaper on the side apart from the tip end of the cutting edge.

(3) The present invention is to provide the method for manufacturingmetal parts with split ends joined according to the method defined inthe method (1) stated above, wherein the press-splitting is performed bypressing the slitting punch or the cleaving punch against the face ofone end of the metal plate, or the solid metal rod, and against thecleft of the split repeating operations of securing the metal plate, orthe solid metal rod, using the clamping device after moving either theclamping device on at least one side of the clamping devices or themetal plate, or the metal rod, by a specified stroke in one direction.

(4) The present invention is to provide the method for manufacturingmetal parts with split ends joined according to the method defined inthe method (1) stated above, wherein, in the process of splitting themetal plate, or the solid metal rod, longitudinally with respect to themetal plate, or the solid metal rod, by slitting or cleaving and in theprocess of advancing the splitting by the slitting or cleaving further,the press-splitting by the slitting punch or the cleaving punch isperformed with a progressive transfer method comprised of separateprocessing stages, wherein, in each time of the press-splittingoperation, the position of at least one side of the clamping device thatpinches both sides of the metal plate or that pinches at least twoopposite-facing portions on the periphery of the solid metal rod ismoved in advance by a stroke corresponding to the distance from one endof the metal plate, or the solid metal rod, to the distal end of asplit-desired portion.

(5) The present invention is to provide the method for manufacturingmetal parts with split ends joined according to the method defined inthe method (1) stated above, wherein a groove cut or a nick line is madein advance on at least one of places in the peripheral portion of theend part of the metal plate, or the solid metal rod, wherein the placesare a place where the slitting punch or the cleaving punch is applied toand a place periphery of the metal plate that corresponds to thesplit-desired portion of the metal plate, or the solid metal rod.

(6) The present invention is to provide the method for manufacturingmetal parts with split ends joined according to the method defined inthe method (1) stated above, wherein the joining of the split ends ofthe metal plate, or the split ends of the metal rod, and another metalplate is a joining between dissimilar metals.

(7) The present invention is to provide the method for manufacturingmetal parts with split ends joined according to the method defined inthe method (2) stated above, wherein the press-splitting is performed bypressing the slitting punch or the cleaving punch against the face ofone end of the metal plate, or the solid metal rod, and against thecleft of the split repeating operations of securing the metal plate, orthe solid metal rod, using the clamping device after moving either theclamping device on at least one side of the clamping devices or themetal plate, or the solid metal rod, by a specified stroke in onedirection.

(8) The present invention is to provide the method for manufacturingmetal parts with split ends joined according to the method defined inthe method (2) stated above, wherein, in the process of splitting themetal plate, or the solid metal rod, longitudinally with respect to themetal plate, or the solid metal rod, by slitting or cleaving and in theprocess of advancing the splitting by the slitting or cleaving further,the press-splitting by the slitting punch or the cleaving punch isperformed with a progressive transfer method comprised of separateprocessing stages, wherein, in each time of the press-splittingoperation, the position of at least one side of the clamping device thatpinches both sides of the metal plate or that pinches at least twoopposite-facing portions on the periphery of the solid metal rod ismoved in advance by a stroke corresponding to the distance from one endof the metal plate, or the solid metal rod, to the distal end of asplit-desired portion.

(9) The present invention is to provide the method for manufacturingmetal parts with split ends joined according to the method defined inthe method (2) stated above, wherein a groove cut or a nick line is madein advance on at least one of places in the peripheral portion of theend part of the metal plate, or the solid metal rod, wherein the placesare a place where the slitting punch or the cleaving punch is applied toand a place periphery of the metal plate that corresponds to thesplit-desired portion of the metal plate, or the solid metal rod.

(10) The present invention is to provide the method for manufacturingmetal parts with split ends joined according to the method defined inthe method (2) stated above, wherein the joining of the split ends ofthe metal plate, or the split ends of the metal rod, and another metalplate is a joining between dissimilar metals.

Applying the present invention makes it practicable to split an end partof a metal plate having shapes other than circular or disk-like shape,for example, any of a rectangular, polygonal, or elliptical shape, or anend part of a metal rod having a cross-section of any of a circular,elliptical, rectangular, or polygonal shape, by performing thepress-splitting of the end part of a metallic material a number of timescontinuously using a slitting punch or a cleaving punch. In addition, inthe multiple press-splitting described above, it becomes practicable toadjust the length of the incision in the splitting freely within thedesired range by adjusting the position of the clamping device forpinching a metal plate, or a metal rod, in each time of thepress-splitting operation. Further, an end splitting method, which hasan excellent productivity with lowered manufacturing cost, can be builtby performing the press-splitting continuously with one direction feedat a specified stroke or with a progressive transfer method.Furthermore, applying the slitting punch or the cleaving punch on thesplitting position becomes easy by making in advance a groove cut or anick line on at least any one of the metal plate or a periphery of themetal plate that corresponds to the split-desired portion of the metalrod, permitting a highly accurate end splitting with a simple manner.Moreover, the splitting by the press-splitting develops along the groovecut or the nick line making the end splitting easy.

The metal parts manufacture by the end splitting method of the presentinvention is compatible with not only changing freely the length ofsplit portion but also adjustment of split thickness freely to a desiredthickness by changing the thickness ratio in the split plane or bymachining for folding the split portion. Thereby, it becomes possible tomanufacture high-value added metal parts that were hard to manufactureby the conventional method. In addition to the above, the metal partsmanufactured by the end splitting method of the present invention isfeasible for employing a new bonding method that was unprecedented. Forexample, when bonding a metal part by the present invention with theother metal parts, bonding them in a condition of three-layer build-up,wherein the other metal part is sandwiched, will largely increase thebonding strength and joining reliability. Therefore, the applicabilityof the bonding method for metal parts by the present invention to thefields that require more increased thermal resistivity and more enhancedenvironment resistance can significantly expand.

BRIEF DESCRIPTION OF THE DRAWINGS

By way of example, a specific embodiment of the disclosed device willnow be described, with reference to the accompanying drawings, in which:

FIGS. 1A to 1D are an explanatory illustration of steps of thepress-splitting in the first embodiment of the method for splitting theend part of a metal plate, or a metal rod, according to the presentinvention, wherein the slitting punch is used while moving the clampingdevice.

FIGS. 2A to 2D are an explanatory illustration of steps of thepress-splitting in the second embodiment of the method for splitting theend part of a metal plate, or a metal rod, according to the presentinvention, wherein the slitting punch is used while moving the metalplate, or the metal rod.

FIGS. 3A to 3D are an explanatory illustration of steps of thepress-splitting in the third embodiment of the method for splitting theend part of a metal plate, or a metal rod, according to the presentinvention, wherein the cleaving punch is used while moving the clampingdevice.

FIGS. 4A to 4D are an explanatory illustration of steps of thepress-splitting in the fourth embodiment of the method for splitting theend part of a metal plate, or a metal rod, according to the presentinvention, wherein the cleaving punch is used while moving the metalplate, or the metal rod.

FIGS. 5A and 5B are an explanatory illustration of steps of the endsplitting method according to the present invention, wherein theprogressive transfer method is employed.

FIGS. 6A to 6C are an explanatory illustration of steps of the endsplitting method according to the present invention, wherein a groovecut or a nick line is provided on the metal plate, or the metal rod, inadvance.

FIGS. 7A to 7D are an explanatory illustration of steps of the end partsplitting in the fifth embodiment of the present invention, wherein theend splitting is performed with a cutting plane formed in the end partof the metal plate, or the metal rod, to create a boundary of splittingto split partially.

FIGS. 8A and 8B are sectional views that show an example of the shape ofcutting edge of the slitting punch or the cleaving punch used in the endsplitting method of the present invention.

FIGS. 9A to 9F are an explanatory illustration of steps of manufacturinga metal part having Figure-T shape manufactured by the sixth embodimentof the present invention.

FIGS. 10A and 10B are an explanatory illustration of steps ofmanufacturing a metal part having Figure-L shape raised brimmanufactured by the seventh embodiment of the present invention.

FIGS. 11A and 11B are illustrations that show a method for manufacturingmetal parts with split ends joined in the eighth embodiment of thepresent invention applied between the split ends of the metal plate, orthe split ends of the metal rod, and the other metal plate.

The drawings are not necessarily to scale. The drawings are merelyrepresentations, not intended to portray specific parameters of thedisclosure. The drawings are intended to depict example embodiments ofthe disclosure, and therefore are not be considered as limiting inscope. In the drawings, like numbering represents like elements.

DETAILED DESCRIPTION

Numerous embodiments of improved screw pumps in accordance with thepresent disclosure will now be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the present disclosure are presented. The screw pump of the presentdisclosure may, however, be embodied in many different forms and shouldnot be construed as being limited to the embodiments set forth herein.Rather, these embodiments are provided so that this disclosure willconvey certain example aspects of the screw pump to those skilled in theart. In the drawings, like numbers refer to like elements throughoutunless otherwise noted.

To split an end part of a metal plate having shapes other than circularor disk-like shape, i.e., any of a rectangular, polygonal, or ellipticalshape, or an end part of a metal rod having a cross-section of any of acircular, elliptical, rectangular, or polygonal shape, the end splittingmethod by the present invention applies a press-splitting on the endpart of such metallic material a number of times continuously using aslitting punch or a cleaving punch; this is the first feature. Further,the position of a clamping device for pinching the metal plate, or themetal rod, is adjusted in each time of such multiple operation of thepress-splitting in order not only to form an even split face but also toadjust freely the length of incision in the split portion; this is thesecond feature.

Unlike splitting metallic materials having a circular or a cylindricalshape such as a conventional style of V-pulley or break shoe, splittingan end part of a metal plate having any of a rectangular, polygonal, orelliptical shape, or an end part of a metal rod having a cross-sectionof any of a circular, elliptical, rectangular, or polygonal shape, asare in the present invention, is not compatible with a method thatapplies a slitting punch or a cleaving punch for creating split plane ina rotating manner, or with a method that processes a metallic workpiecesuch as metal plate, or a metal rod, giving rotation to the workpiece.Further, what applying the press-splitting process using the slittingpinch or the cleaving punch to the end part of the metal plate, or themetal rod, simply one time can form is a protrusion about a lug level;it is therefore hard to form a split of enough length (or depth). Tomake the split longer, use of a cutter instead of the slitting punch orthe cleaving punch could be an alternative method. However, cutting theend part longitudinally with a cutter cannot avoid thickness reductionin the metal plate, or the metal rod, due to the thickness of the cutterused, which makes it hard to apply the cutter-cutting to a thin metalplate or a small-diameter metal rod. In addition, cutting with a cutternot only invites roughening the split face attributable to cuttingdebris or lowering in the work efficiency due to generation offrictional heat but also makes the processing complicated because suchcutting requires cleaning of the split faces after cutting. Thus, thepresent invention applies the press-splitting to the end part of themetal plate, or the metal rod, using a slitting punch or a cleavingpunch consecutively repeating many times to lengthen (or deepen) thesplit portion. The method for splitting an end part by the presentinvention comprises mainly two processing stages described below.

The first processing stage comprises the steps of: securing a metalplate by pinching both sides thereof with a clamping device or securinga metal rod by pinching at least two opposite-facing portions on theperiphery thereof with a clamping device; applying a slitting punch or acleaving punch against the cross-sectional face of one end of the metalplate, or the metal rod, to be split; and splitting the metal plate, orthe metal rod, longitudinally by slitting or cleaving with apress-splitting. The second processing stage comprises the step ofadvancing the splitting by giving again the press-splitting with theslitting punch or the cleaving punch at the cleft of the split createdin the first processing stage, wherein this press-splitting operation isperformed one time or repeated two or more times until the split length(or depth) reaches the specified range. In the first and secondprocessing stages, the position of at least one side of the clampingdevice that pinches both sides of the metal plate or that pinches atleast two opposite-facing portions on the periphery of the metal rod is,in each time of the press-splitting operation, moved in advance by astroke corresponding to the distance from one end of the metal plate, orthe metal rod, to the distal end of a split-desired portion. In thismovement, it is preferable to adjust the position of the clamping devicethat pinches the metal plate, or the metal rod, by moving either theclamping device on at least one side of the clamping devices or themetal plate, or the metal rod, so that one end of the clamping device onat least one side of the clamping devices will come to almost the sameposition of the distal end of the split-desired portion from one end ofthe metal plate or the metal rod. Thereby, the split length at the endpart of the metal plate, or the metal rod, can be adjusted within thespecified range.

In the present invention, the rectangular shape means a shape of asquare or a cuboid and the polygonal shape means shapes of polygonshaving five or more sides or triangle except for the tetragon butincluding those variant having irregular shapes; however, those polygonshaving shapes close to circles, particularly those having more sidesthan 12-side, are excluded. A metal plate of an elliptical shape means aplate having a long side A and a short side B in a ratio (A/B) of 1.2 ormore. As the metal rod that the present invention relates, a rod havinga circular or an elliptical cross-section is mainly used; however, a rodhaving a rectangular or a polygonal cross-section may be used as ametallic workpiece as well.

The end splitting method of the present invention is a method forsplitting longitudinally with respect to the metal plate, or the metalrod, having above-stated shape. In the invention, the term “splittinglongitudinally” means, in the case of the metal plate, that thesplitting develops in the width-wise direction or in the depth-wisedirection, wherein the workpiece is split so that the split plane willspread within the thickness of the metal plate. In the case of the metalrod, that term means that the cross-section of the metal rod is split inthe lengthwise of the rod. Further, the end splitting method of thepresent invention can split the cross-section of the metal plate, or themetal rod, not only into equal sections but also into a desiredsection-ratio depending on the shape or function that theforming-completed workpiece may require. In addition, not only splittinginto two sections, the cross-section of the metal plate, or the metalrod, may be split also into three or more sections. In such event,lengths (or depths) of splits can be equal or different each other.

The present invention does not have any particular limitation tomaterial nature of the metal plate, or the metal rod, to which theinvented end splitting method apply. However, copper, aluminum,stainless steel, brass, and iron are suitable material, because theyhave a wide range of applicability, a great market-needs as a highvalue-added metal product, and capability of responding to a demand onlowering manufacturing cost.

The following explains embodiments of the end splitting method by thepresent invention.

First Embodiment

FIGS. 1A to 1D are an explanatory illustration of steps of thepress-splitting in the first embodiment of the method for splitting theend part of a metal plate 1, or a metal rod 2, according to the presentinvention, wherein a slitting punch 4 is used while moving a clampingdevice 3. As FIGS. 1A to 1D illustrate, the end splitting method in thisembodiment comprises the steps of: securing the metal plate 1 or, themetal rod 2, by pinching with the clamping device 3 (FIG. 1A);performing press-splitting applying the slitting punch 4 on the face ofone end of the metal plate 1, or the metal rod 2 (FIG. 1B); moving theclamping device 3 to the split-desired position and securing again themetal plate 1, or the metal rod 2, by pinching with the clamping device3 to secure (FIG. 1C); and applying the slitting punch 4 on the cleft ofthe split portion to advance splitting by the press-splitting (FIG. 1D).The steps illustrated in FIGS. 1C and 1D are repeated until the splitlength (or depth) reaches the specified extent. Finally, the metal plate1, or the metal rod 2, is formed into a shape having a split plane asillustrated in a perspective view in FIG. 1D. After that, the end-splitmetal plate, or metal rod, undergoes press-forming, crimping orpress-squeezing to be formed into a metal product having a shape of, forexample, Figure-T, Figure-L, or Figure-Y.

In the step illustrated in FIG. 1A, the metal plate 1 is secured byclamping device 3 with both sides pinched and the metal rod 2 is securedby clamping device 3 with at least two opposite-facing portions on theperiphery thereof pinched. Pinching at least two opposite-facingportions on the periphery of the metal rod 2 makes securing the metalrod 2 tight. In addition, such a clamping device that holds entirecircumference of the metal rod 2 may be usable as a method for securingthe metal rod 2.

In the step illustrated in FIG. 1B, the end splitting of the metal plate1, or the metal rod 2, using the slitting punch 4 is performed to theposition almost the same as the position of one end of the clampingdevice 3 that pinches the metal plate 1, or the metal rod 2. In theportion pinched with the clamping device 3, breakage or cleaving of thetissue of the metallic workpiece is suppressed due to compressive stressgenerated by the pinching force caused by the clamping device 3, whichprevents occurrence of splitting during the press-splitting by theslitting punch 4. Therefore, adjusting the working position of theclamping device can control freely the length of splitting. That “theposition of one end of the clamping device 3 that pinches the metalplate 1, or the metal rod 2, is almost the same as the position of thedistal end of the split-desired portion” means a place where one end ofthe clamping device 3 sits is within the range of −3 mm to +1 mm, morepreferably −1 mm to +0.5 mm, from the distal end of the split-desiredportion. In this, the place −3 mm means a position where the end A ofthe clamping device 3 indicated in FIG. 1B sits at a point 3 mm apartdownward from the distal end B of the split-desired portion. Incontrast, the place +1 mm means a position where the end A sits at apoint 1 mm apart upward from the distal end B; this means that thelength of the development of splitting within the portion pinched withthe clamping device is 1 mm inward from the position of the end A at amaximum. Thus, the clamping device 3 moreover has a function toterminate the development of the splitting.

In general, when the pressure in the press-splitting by the slittingpunch 4 is high or the applying speed of the press-splitting is high,positional deviation of the distal end of the end-splitting portion fromone end of the clamping device 3 tends to become large. Such state isnot desirable, because the state invites not only difficulty in theadjustment of the splitting length (or depth) on the end of splitportion but also deformation of the metal plate 1, or the metal rod 2,and easiness of occurrence of minute cracks at the distal end of thesplit. Further, if the split-forming pressure is too low or thesplit-forming speed is too low, the splitting is not fully achieved andresults in a large positional deviation from one end of the clampingdevice 3. In addition to the above in such event, a problem arises inthat the work efficiency in the splitting will become low. Therefore,the present invention requires the optimizing of the pressure and speedof the split-forming in performing the press-splitting so that thepositional deviation of the distal end of the end split portion from oneend of the clamping device 3 will be minimized. This means that thebringing of the position of one end of the clamping device 3 forpinching the metal plate 1, or the metal rod 2, to almost the sameposition as the distal end of the split-desired portion will befollowed, as a result, by a setting that the conditions for thepress-splitting by the end splitting method of the present invention isoptimized. In this embodiment, the press-splitting is performed underthe conditions that the pressing load and the press-loading speed are inthe range of 1 to 10 tons and 1 to 50 mm/s respectively. In addition, inview of the balance between performance and cost of a press apparatus,it is preferable that the press load and the press-loading speed shouldbe in the range of 2 to 5 tons and 2 to 10 mm/s respectively.

In the step illustrated in FIG. 1C, the clamping device 3 moves to thesplit-desired position with the metal plate 1, or the metal rod 2,clamped. In this embodiment, both sides of the clamping device 3 thatpinches both sides of the metal plate 1, or that pinches at least twoopposite-facing portions on the periphery of the metal rod 2, are movedusually simultaneously. The moving distance may be the same as, ordifferent from, the one in the step illustrated in FIG. 1A. In thisoperation, changing the conditions of the pressing load and thepress-loading speed in the press-splitting with the slitting punch 4 isnot always necessary because such conditions have an allowance to someextent. However, if a change in the moving distance is likely to belarge or an optimization of the press-splitting conditions is needed,such press-splitting conditions may be changed. After the moving, theclamping device 3 clamps again the metal plate 1, or the metal rod 2, tosecure by pinching. The preferred range of moving distance in the stepsillustrated in FIGS. 1A and 1B is 0.01 to 10 mm at a time, morepreferably 0.5 to 5 mm. The moving distance less than 0.01 mm is notpreferable, because the splitting consumes longer time invitingsignificantly low work efficiency. The moving distance over 10 mminvites a problem not only such that deformation of the metallicworkpiece becomes large but also such that the cutting edge of the punchwill break or largely abrade. In the present invention, few problemslike the one mentioned above will occur when the moving distance of theclamping device 3 is within the range of 0.5 to 5 mm.

In the step illustrated in FIG. 1D following the above, thepress-splitting is performed applying the slitting punch 4 on the cleftof the split portion created in the step (B) stated above to splitagain. To advance the splitting further, the steps illustrated in FIGS.1C and 1D are repeated until the length (or depth) reaches the specifiedextent. In the repetition of the steps illustrated in FIGS. 1C and 1D,the moving distance of the clamping device 3 may be a constant value, orinstead, may be changed at each step. For example, to split highlyaccurately as designed, the moving distance of the clamping device 3 canbe made, only at the last operation in the press-splitting, shorter thanthe one in the previous operation. Even in the case that thepress-splitting conditions is required to be changed due to change inthe split length, an automatic control is applicable to the move andpinch-clamp actions of the clamping device 3, the press-splittingconditions, or other working conditions using a control device such as acomputer by grasping in advance the relationship between the splitlength and press-splitting conditions. This automatic control is appliedto an end splitting method such that the splitting advancesconsecutively in one direction at a specified stroke, or to aprogressive transfer end splitting method, wherein each of the steps inthe press-splitting is separated and arrayed in a line so that aplurality of press-splitting steps will be performed progressively. Inthe present invention, the repetition of the press-splitting illustratedin FIGS. 1A to 1D may be applied not only to a method in which therepetition is performed consecutively with one unit of equipment or inone series of working processes, but also to a method in which therepetition is performed separately as an independent step. In suchapplication, the automatic control method of the move of the clampingdevice 3 and the press-splitting conditions are still usable as aproduction control tool.

Second Embodiment

FIGS. 2A to 2D are an explanatory illustration of steps of thepress-splitting in the second embodiment of the method for splitting theend part of a metal plate 1, or a metal rod 2, according to the presentinvention, wherein a slitting punch 4 is used while moving the metalplate 1, or the metal rod 2. In this embodiment, securing the metalplate 2, or the metal rod 2, by pinching with a clamping device 3 (FIG.2A) and performing press-splitting applying the slitting punch 4 on theface of one end of the metal plate 1, or the metal rod 2 (FIG. 2B), arethe same steps as those in the first embodiment illustrated in FIGS. 1Aand 1B. The difference from the steps indicated in FIGS. 1A and 1B isthat the metal plate 1, or the metal rod 2, is moved instead of movingthe clamping device 3. The embodiment employs a step, in which the metalplate 1, or the metal rod 2, is secured again by pinching with theclamping device 3 after the metal plate 1, or the metal rod 2, is movedto the split-desired position (FIG. 2C). Then, similarly as in the stepillustrated in FIG. 1D, the slitting punch 4 is applied on the cleft ofthe split portion to advance splitting by the press-splitting (FIG. 2D)and repeat the steps illustrated in FIGS. 2C and 2D in accordance withthe split length.

In the step illustrated in FIG. 2C, the moving of the metal plate 1, orthe metal rod 2, can be achieved by sliding a jig for example, whichsupports the metallic workpiece, by a split-desired distance. In thatmoving, the clamping device 3 for pinching is loosened slightly and thentightened to pinch again, after the metal plate 1, or the metal rod 2,was moved. Further, the slitting punch 4 should be retracted in advanceso that the movement of the metal plate 1, or the metal rod 2, will notbe impeded. This obstruction prevention may also be achieved by clearingthe space between the clamped metal plate 1, or metal rod 2, and theslitting punch 4 in advance of the step illustrated in FIG. 2C, whichpermits the metal plate 1, or the metal rod 2, can move successivelywithout obstruction. It should be noted that the steps illustrated inFIGS. 2A, 2B, and 2C are basically the same as the steps indicated inFIGS. 1A, 1B, and 1C, therefore, the end splitting is performed in amanner corresponding to the explanation of the first embodiment. In thisembodiment, the distance of one movement of the metal plate 1, or themetal rod 2, is the same as the one specified in the first embodimentfor the range of one move of the clamping device 3.

Third Embodiment

FIGS. 3A to 3D are an explanatory illustration of steps of thepress-splitting in the third embodiment of the method for splitting theend part of a metal plate 1, or a metal rod 2, according to the presentinvention, wherein a cleaving punch 5 is used while moving a clampingdevice 3. As FIGS. 3A to 3D illustrate, the end splitting method in thisembodiment comprises the steps of: securing the metal plate 1, or themetal rod 2, by pinching with the clamping device 3 (FIG. 3A);performing press-splitting, applying the cleaving punch 5 on the face ofone end of the metal plate 1, or the metal rod 2, along one face of theclamping device 3 on one side (FIG. 3B); moving one side of the clampingdevice 3, which is disposed on the other side of the face on which theclamping device 3 stated above is arranged, to the split-desiredposition and securing again the metal plate 1, or the metal rod 2, bypinching with the clamping device 3 to secure (FIG. 3C); and applyingthe cleaving punch 5 on the cleft of the split portion to advancesplitting by the press-splitting (FIG. 3D). The steps illustrated inFIGS. 3C and 3D are repeated until the split length (or depth) reachesthe specified extent. Finally, the metal plate 1, or the metal rod 2, isformed into a shape having a split plane as illustrated in a perspectiveview FIG. 3D. After that, the end-split metal plate or metal rodundergoes press-forming, crimping, or press-squeezing to be formed intoa metal part having a shape of, for example, Figure-T, Figure-L, orFigure-Y.

In the step illustrated in FIG. 3A, the metal plate 1 is secured byclamping device 3 with both sides pinched and the metal rod 2 is securedby securing device 3 with at least two opposite-facing portions on theperiphery thereof pinched. Pinching at least two opposite-facingportions on the periphery of the metal rod 2 makes clamping the metalrod 2 tight. In addition, a clamping device that holds entirecircumference of the metal rod 2 may be usable as a method for securingthe metal rod 2. In the end splitting method using the cleaving punch 5like this embodiment, placing the metal plate 1, or the metal rod 2,flat makes processing easy. Therefore, the clamping device that isarranged under the workpiece may have a flat bottom. Further in thepresent embodiment, fixing one side of the clamping device 3 (theclamping device that is arranged on the lower side in FIGS. 3A to 3D),the other side of the clamping device that is disposed on the other sideof the face (the clamping device that is arranged on the upper side inFIGS. 3A to 3D) may be configured in a mobile style. Thereby, the movingof the clamping device 3 becomes easy and, further, the accuracy ofpositioning at the distal end of the split-desired portion on the metalplate 1, or the metal rod 2, is improved. Similarly, the clamping device3 is moved in the step illustrated in FIG. 3C. In this moving, themoving distance can be the same as the one in the step illustrated inFIG. 3A or can be different one. For the same reason as stated in thefirst embodiment, the preferred range of the moving distance at a timeis 0.01 to 10 mm, more preferably 0.5 to 5 mm.

In the step illustrated in FIG. 3B, the end splitting of the metal plate1, or the metal rod 2, using the cleaving punch 5 is performed to theposition almost the same as the position of one end of the pinchingelement of the clamping device 3 on one side that pinches the metalplate 1 or the metal rod 2. In FIG. 3B, in the portion pinched betweenthe upper element of the clamping device 3 and the lower element of theclamping device 3, breakage or cleaving of the tissue of the metallicworkpiece is suppressed due to compressive stress generated by thepinching force caused by both elements of the clamping device 3, whichprevents occurrence of splitting during the press-splitting by thecleaving punch 5. On the other hand, the portion not pinched by theupper element of the clamping device 3 is splittable because the portionreceives no clamping force. Therefore, adjusting the working position ofthe clamping device 3 can control freely the length of splitting. That“the position of one end of the clamping device that pinches the metalplate 1, or the metal rod 2, is almost the same as the position of thedistal end of the split-desired portion” means, as is the same as in thefirst embodiment, a place where one end of the clamping device 3 sits iswithin the range of −3 mm to +1 mm, more preferably −1 mm to +0.5 mm,from the distal end of the split-desired portion. Further, thepress-splitting conditions in this embodiment employ a similar range ofthe pressing load and the press-loading speed to those in the firstembodiment. In the step illustrated in FIG. 3D, the press-splitting isperformed with the cleaving punch 5 under the similar conditions. Theconditions of the pressing load and the press-loading speed in thepress-splitting with the cleaving punch 5 is not always necessary to bechanged from the ones in the step illustrated in FIG. 3B because suchconditions have an allowance to some extent. However, if a large changein the moving distance in the step illustrated in FIG. 3B from theinitial length is intended or an optimization of the press-splittingconditions is needed, such press-splitting conditions may be changed.

The end splitting method illustrated in FIGS. 3A to 3D is able toposition and secure the end-splitting portion of a metal plate, or ametal rod, easily with high-accuracy using the clamping device 3arranged lower part; therefore, the splitting of the end part into athin thickness becomes practicable. Further, not only a simpletwo-portion splitting but also a three or more multi-portion splittingis easily achieved by splitting one portion by one portion from the toptoward bottom. Thus, the method has an advantage of being able tomanufacture metal parts applicable to various use.

Fourth Embodiment

FIGS. 4A to 4D is an explanatory illustration of steps of thepress-splitting in the fourth embodiment of the method for splitting theend part of a metal plate 1, or a metal rod 2, according to the presentinvention, wherein a cleaving punch 5 is used while moving the metalplate 1, or the metal rod 2. The end splitting method in this embodimentcomprises the steps of: securing the metal plate 1, or the metal rod 2,by pinching with a clamping device 3 (FIG. 4A); and performingpress-splitting, applying the cleaving punch 5 on the face of one end ofthe metal plate 1, or the metal rod 2, along the face of the clampingdevice 3 on one side (FIG. 4B), which are the same as the stepsillustrated in FIGS. 3A and 3B. The difference from the stepsillustrated in FIGS. 3A and 3B is that the metal plate 1, or the metalrod 2, is moved instead of moving the clamping device 3 on one side.This embodiment employs the step illustrated in FIG. 4C moving the metalplate 1, or the metal rod 2, together with one side of the clampingdevice 3 securing the bottom side of the metal plate 1, or the metal rod2, to the split-desired position and then pinching again to secure themetal plate 1, or the metal rod 2, with the clamping device 3 securingthe top side of the metal plate 1, or the metal rod 2. In the stepillustrated in FIG. 4C, a method moving at first the clamping device 3securing the bottom side to create a clearance at the top of the metalplate 1, or the metal rod 2, and then moving the metal plate 1, or themetal rod 2, may be employed. Following the above, the step illustratedin FIG. 4D performing the press-splitting by applying the cleaving punch5 on the cleft in the split face to advance splitting is progressedsimilarly as illustrated in FIG. 3D. Then, repeat the steps illustratedin FIGS. 4C and 4D in accordance with the desired split length.

In the step illustrated in FIG. 4C, the moving of the metal plate 1, orthe metal rod 2, can be achieved by sliding a jig for example, whichsupports the metallic workpiece, by a split-desired distance. In thatmoving, the clamping device 3 for pinching is loosened slightly and thentightened to pinch again, after the metal plate 1, or the metal rod 2,was moved. Further, the cleaving punch 5 should be retracted in advanceso that the movement of the metal plate 1, or the metal rod 2, will notbe impeded. This obstruction prevention may also be achieved by clearingthe space between the clamped metal plate 1, or metal rod 2, and theslitting punch in advance of the step (c), which permits the metal plate1, or the metal rod 2, can move successively without obstruction. Itshould be noted that the steps illustrated in FIGS. 4A, 4B and 4C arebasically the same as the steps indicated in FIGS. 3A, 3B and 3C,therefore, the end splitting is performed in a manner corresponding tothe explanation of the third embodiment. In this embodiment, thedistance of one movement of the metal plate 1, or the metal rod 2, isthe same as the one specified in the third embodiment for the range ofone move of the clamping device.

Next, the following explains an end splitting method by the presentinvention with improved productivity in each of the first to fourthembodiments. The method employs a sequential operation of thepress-splitting.

For steps illustrated in FIGS. 1 to 4, an operation that covers movingboth of or one side of the clamping device 3 by a stroke correspondingto the specified split length in one direction and then performing thepress-splitting on the end part of the metal plate 1, or the metal rod2, is defined as one step. This end splitting method sequentially andautomatically repeats that step to advance the end splitting until thesplitting finally reaches the desired length (or depth). In this method,instead of moving the clamping device 3, moving continuously andautomatically the metal plate 1, or the metal rod 2, which is a metallicworkpiece, by a specified stroke may be employed to perform the steps(A) to (D) illustrated in FIGS. 1 to 4 sequentially in one direction. Inthis processing, the position of the slitting punch 4 or the cleavingpunch 5 before starting the press-splitting is regulated by a computerusing a position sensor as specified. Likewise, both sides or one sideof the clamping device 3 is also automatic-controlled to move to thespecified position. Further, as explained previously, in the case thatthe press-splitting conditions is required to be changed due to changein the split length, an automatic control is applicable to the move andpinch-clamp actions of the clamping device 3, the press-splittingconditions, or other working conditions using a control device such as acomputer by grasping in advance the relationship between the splitlength and press-splitting conditions.

As another method for the end splitting by a sequential operation of thepress-splitting, a progressive transfer line manufacturing configurationcan be cited. The press-splitting steps illustrated in FIGS. 1 to 4 areseparated into a single step of processing and arranged in an in-lineconfiguration of a series-processing layout, in which plural steps inthe press-splitting operation are performed progressively. The followingexplains the steps in the progressive transfer end splitting methodreferring to FIGS. 5A and 5B. The end splitting method illustrated inFIGS. 5A and 5B is an example, in which the end splitting is performedby the press-splitting using a slitting punch 4. In the steps of themethod for splitting end part of a metal plate 1, FIG. 5A and FIG. 5Bare a plan view and a side view respectively.

The progressive transfer end splitting method performs the splitting ofthe end part of a metal plate as illustrated in FIGS. 5A and 5B. In themethod, a long metal material 6 having a specified thickness is fedintermittently. At the first stage of processing, a metal plate 1 isshaped into rectangular, then at the second stage, the metal plate 1 ispinched with a clamping device 3 and undergoes the first splitting ofthe end part in the press-splitting processes by the slitting punch 4.At the third and successive stages, the metal plate 1 experiences themove of the clamping device 3 and is again pinched with the clampingdevice 3 after its move to undergo the press-splitting by the slittingpunch 4. Thus, the splitting of the end part of the metal plateprogresses. For simplicity, FIGS. 5A and 5B illustrate only the stepsdown to the fifth stage. In the present invention however, the number ofthe processing stages after the third stage may be changed and the totalnumber of the processing steps and the length of the long metal material6 can be determined in accordance with the split length per one step andthe last split length to complete the splitting processes. The length ofthe long metal material 6 changes depending not only on the number ofthe processing steps in the press-splitting but also on the shape of themetal plate 1, method of machining, shape of processing mold, or otherfactors. The long metal material 6 is cut into pieces for successivefinal processing or cut into pieces after the final processing.

In the intermittent feed of the long metal material 6 illustrated inFIGS. 5A and 5B, inserting a mold pin in a sprocket hole 7 makes thelong metal material 6 to be placed in position and prevents theoccurring of back-lash during press-splitting and processing. Further,the metal plate 1, after processed into a rectangular shape at the firststage illustrated in FIGS. 5A and 5B, may undergo bending at aright-angle at the second stage, and then, the first splitting of theend part at the third stage, and further then, may be advanced to theend splitting by the cleaving pinch 4 at the fourth or successivestages. In addition, the present invention can employ a simultaneousapplication of the same processing on the plural metal plates by feedingthe long metal material 6 intermittently in a batch of two or morenumbers of the metal plate 1, not an intermittent feeding in a one byone manner. Furthermore, the long metal material 6 may undergo the endsplitting being fed in a lead frame feeding manner by dividingprocessing steps into a lead frame basis handling the long metalmaterial 6 as one lead frame. The progressive transfer methodillustrated in FIGS. 5A and 5B is a press-splitting with a slittingpunch; the present invention can employ the same progressive transfermethod in the case of press-splitting with a cleaving punch.

As stated above, by performing the press-splitting with a slitting punchor a cleaving punch consecutively in one direction or in a progressivetransfer method at a specified stroke, an end splitting system that hasan excellent productivity with lowered manufacturing cost can beestablished.

The end splitting method in the present invention may employ a meansexplained below to increase the processing speed and to form an evensplit face.

As FIG. 6A illustrates, the means is such that a groove cut 8 or a nickline 9 is made in advance on at least one of places in the peripheralportion of the end part of the metal plate 1, or the metal rod 2,wherein the places are a place where the slitting punch or the cleavingpunch is applied to and a place periphery of the metal plate 1, or themetal rod 2, that corresponds to the split-desired portion of the metalplate 1, or the metal rod 2. The groove cut 8 made in the end splittingmethod by the present invention is formed from the surface of the metalplate 1, or the metal rod 2, to a depth not deeper than the width of themetal plate 1 or not deeper than ⅕ of the diameter of the metal rod 2;that is, the groove cut 8 does not mean a cutting plane. The groove cut8 or the nick line 9 can be made automatically in advance using ascriber, a cutter, a die, or other known tool. It is also possible toform a cut groove using a chemical. In this method, a mark-off line isscribed and a trace quantity of a chemical or the like is applied on thescribed line, then the chemical-applied portion of metal will be partlydissolved creating a cut groove.

By making above-mentioned groove cut 8 or nick line 9 on the splittingposition in the cross-section of the metal plate or the metal rod,applying the slitting punch 4 or the cleaving punch (not illustrated) onthe splitting position becomes easy permitting a highly accurate endsplitting with a simple manner. Further, forming the groove cut 8 or thenick line 9 on the periphery of the metal plate 1, or the metal rod 2,as illustrated in FIGS. 6B and 6C, makes the splitting by thepress-splitting with the slitting punch develop along the groove cut 8or the nick line 9 making the end splitting easy. In this case, theforming of the groove cut 8 or the nick line 9 to the distal end of thesplit-desired portion makes it possible to give a limitation of thesplit length (or depth) to a desired length in advance.

Fifth Embodiment

FIGS. 7A to 7D illustrate the steps in a method for splitting partiallyan end part of a metal plate 1, or a metal rod 2, by a press-splittingwith a slitting punch 4. In this embodiment, to split partially the endpart, a cutting plane is provided perpendicularly to the split face inthe cross-section of a metal plate, or a metal rod. First, one cuttingplane 10 is formed in the thickness direction of the metal plate 1.Then, the slitting punch 4 is applied on the partial-split-desiredcross-section of the metal plate 1 on the boundary of the cutting plane10 to perform the first processing in the press-splitting (FIG. 7A). Atthat time, two positions on the both sides of the split-desired portionof the metal plate 1 are pinched with a clamping device 3. Then, thepress-splitting with the slitting punch 4 is progressed and finallyeither side of the metal plate 1 on the boundary of the cutting plane 10is partially split (FIG. 7B).

The partial splitting of the end part of the metal rod is performed in abasically same steps as in the metal plate. After forming one cuttingplane 10 in the diameter-wise direction of the metal rod 2, the slittingpunch 4 is applied on the partial-split-desired portion of the metal rod2 on the boundary of the cutting plane 10 to perform the firstprocessing in the press-splitting (FIG. 7C). At that time, two positionson the periphery of the partial-split-desired portion of the metal rod 2are pinched with the clamping device 3. Then, the press-splitting withthe slitting punch 4 is progressed and finally either side of the metalrod 2 on the boundary of the cutting plane 10 is partially split (FIG.7D).

In this embodiment, the forming of the cutting plane 10 to the distalend of the partial-split-desired portion makes it possible in each caseof a metal plate or a metal rod to give a limitation of the split length(or depth) to a desired length in advance. Instead of the slitting punchillustrated in FIGS. 7A to 7D, a cleaving punch may be used. Inaddition, in the case of the metal plate, when the cutting plane isformed to the middle of the thickness of the metal plate, for example toa distance of ½ of the thickness and to a length of ½ of the depth ofthe metal plate 1, the partial splitting can be performed in atearing-off style only on a rectangular portion of the metal, one sideof which is the cutting plane (the part that is the about-⅛-portion ofthe metal plate as illustrated in FIG. 7B). Likewise, in the case of themetal rod, when the cutting plane is formed to the middle in thediameter-wise of the metal rod, for example to a distance to the centerof the metal rod 2 and to a length of ½ of the metal rod 2, the partialsplitting can be performed in a tearing-off style only on a quadrantportion of the metal, one side of which is the cutting plane (the partthat is the about-⅛-portion of the metal rod as illustrated in FIG. 7D).

The end splitting method of this embodiment illustrated in FIGS. 7A to7D may, in the partial splitting of each end part after forming thecutting plane on the splitting boundary at the end part of the metalplate, or the metal rod, employ the sequential press-splitting operationas stated above. The sequential press-splitting can employ a method inwhich the metal plate, or the metal rod, is moved by a specified strokeor the progressive transfer method comprised of separate steps asillustrated in FIGS. 5A and 5B to progress the processing. In this, thecutting step for creating the split boundary on the end part of themetal plate, or the metal rod, may be combined with the press step in aseries of steps. Thereby, the productivity improvement and themanufacturing cost lowering can be achieved.

In the present invention, shaping the cutting edge of the slitting punchor the cleaving punch in a shape as illustrated in FIGS. 8A and 8B forexample can be another method for not only to increase the speed of thepress-splitting but also to form an even split face. FIGS. 8A and 8Billustrate cross-sections of a cutting edge 11 of the slitting punch anda cutting edge 12 of the cleaving punch.

The cutting edge illustrated in FIGS. 8A and 8B is given a taperingshape having at least two taper portions of different angle orcurvature, wherein the taper is provided on both sides in the case ofthe slitting punch and on one side in the case of the cleaving punch.Further, the taper portion of the side close to the tip end of thecutting edge is formed to have an angle or a curvature smaller than thatof the taper on the side apart from the tip end of the cutting edge.Here, the angle of the cutting edge, as illustrated in FIGS. 8A and 8B,means the inclination angle (θ₂ and θ₁) of the cutting edge from thehorizontal line based on the definition that the inclination of thehorizontal line is zero-degree.

In the case of a cutting edge that has one tapered portion, there arisea problem such that the forming of a smooth and flat split face will beprevented, because the end part of metal separated into two may touchthe side face of the cutting edge as the splitting progresses causingthe split face roughening. Further, it may sometimes lower the workefficiency that the end part of metal separated by the splitting touchesthe cutting edge, because such touching prevents a smooth behavior ofthe separated end part of metal. This is a particularly serious problemin performing the press-splitting in a continuous manner. In addition,in the case where the tapered portion close to the cutting edge has alarger angle or a larger curvature compared to the tapered portion apartfrom the cutting edge, there arise also a problem such that the end partof metal separated into two touches the side face of the cutting edge,which is undesirable.

In the end splitting method by the present invention, a slitting punchor a cleaving punch, the cutting edge of each of which has one taperedportion, is usable. It is however preferable to use a punch having acutting edge with the shape illustrated in FIGS. 8A and 8B to improvethe work efficiency. Further, it is preferable to apply asuper-hardening treatment to the cutting edge of the slitting punch orof the cleaving punch to be used in the present invention for increasedstrength or hardness. As the super-hardening treatment, the surfacetreatment by such as carburizing, nitriding, spraying, diamond-likecarbon treating, and TiCN treating may be applicable.

Sixth Embodiment

The following describes a Figure-T shaped metal part as an example ofmetal parts made of a metal plate, or a metal rod, manufactured by theend splitting method of the present invention. FIGS. 9A to 9F are anexplanatory illustration of the steps for manufacturing the Figure-Tshaped metal part using the metal plate processed by the end splitting.

A metal plate 1 is pinched with a clamping device 3 (FIG. 9A), and then,likewise in the second embodiment, undergoes repeatedly thepress-splitting with a slitting punch 4 (FIGS. 9B and 9C) in thelongitudinal direction (in the vertical direction in FIGS. 9A to 9F)with respect to the metal plate 1 until the end of split portion reachesthe specified length (or depth). Then, the half of the split metal endis folded toward the center from the periphery using a press die forbending 13 applying the die so that the split metal end separated intotwo will be surrounded (FIG. 9D). Further, a press die for appressing 14is applied from above to make the surface of the metal plate 1 flat,which is crimped if necessary (FIG. 9E). Thus, the Figure-T shaped metalpart 15 is manufactured (FIG. 9F).

The split metal end of the Figure-T shaped metal part 15 isdouble-folded and formed flat; therefore every portion thereof hasalmost the same thickness (see illustration on the left side of FIG.9F). In the conventional cutting method, it is impossible to make thethickness of the two-fold portion of the split metal end equal to thethickness of the metal plate before splitting due to thickness reductionin the cut portion. Application of the end splitting method of thepresent invention permits manufacturing a Figure-T shaped metal parthaving almost the same thickness at every portion thereof easily fromthe same metal plate as in the metal parts manufactured using bonding bywelding, fusing, or gluing. Therefore, a cost-cut in manufacturing andreduction in use quantity of metallic material can be realized. Further,not having the bonded or glued portion, the Figure-T shaped metal partby the present invention has increased reliability and durability;therefore, the metal part can be used in high-value added parts such asmounts, footing bases, or connection pats having high thermalresistivity and excellent environment resistance.

FIGS. 9A to 9F illustrate such processing steps as folds both sides ofthe split metal end into two-fold. In the present invention, either ofthe sides of the split metal end may be folded into two-fold (see theillustration on the right side of FIG. 9F). In making two-fold, thefolding lengths are not always necessary to be equal each other; thelengths can be changed according to the usage of metal parts. Foldingstyle is not limited to two-fold; three or more folding is practicable.Further, the both sides of the split metal end can be split intodifferent thicknesses.

FIGS. 9A to 9F illustrate an example of the manufacturing of Figure-Tshaped parts using an end splitting method for a metal plate; however,using a metal rod, Figure-T shaped metal parts can be manufactured withthe same processing steps. The fold-back portion of the split metal endcan be one-bodied by such as welding, fusing, or gluing.

Seventh Embodiment

FIGS. 10A and 10B are an explanatory illustration of the steps formanufacturing a metal part 17 to be used as a metal base of an air-tightcontainer, wherein the metal part 17 is manufactured by securing a cover16 of metal or resin on the metal base using any one of methods:press-forming, welding, fusing, and gluing.

As in the third or fourth embodiment stated above, the workpiece isformed to have a raised brim by the press-splitting with a cleavingpunch, and then the raised brim is pressed or drawn with a press dieinto a Figure-L shape (FIG. 10A). Then, the cover 16 of metal or resinis installed on the periphery of the metal part 17 having a Figure-Lshaped raised brim 18, which is followed by a pressing process so that ahollow air-tight container will be manufactured (FIG. 10B). As a methodfor securing the cover 16 on the metal part 17, not only a press-formingbut also bonding by welding or fusing, or gluing may be practicable. Inthis, electronic parts or mechanism elements are mounted in the centerof the metal part 17 having the Figure-L shaped raised brim 18 inadvance of installing the cover 16 of metal or resin. When needed,electrodes and electrode wiring that permit electrical connection withexternal terminals may be provided.

The metal parts of this embodiment can have an elongated split portion.Therefore, a wider space can be created in the flat portion formed bysplitting into two (the part represented by numeral 19 in FIG. 10A).This means that a space for installing bolts or rivets can be assured inmounting the hollow air-tight container on the other base board or part.Further, operations such as press-forming, bonding by welding or fusing,or gluing that is performed when installing the cover 16 of metal orresin becomes easy, because the length of the Figure-L shaped raisedbrim 18 can be assured to some extent.

The metal part manufactured in the fifth and sixth embodiments statedabove is usable after the post-processing applied to the split end partof metal with the face thereof as processed. If needed however, ananticorrosion covering layer may be formed at least on the split face byany method of metallic coating, organic coating, inorganic coating, orchemical conversion treatment. This anticorrosion covering may be formednot only for giving corrosion resistivity against rust but also forenhancing durability, thermal resistivity, or lubricity, or surfacepreparation. Further, such treatments is sometimes applied for thepurpose of giving the metal plate, or the metal rod, a new function suchas fingerprint resistivity, antibacterial, and washing-resistivity.

The metallic coating as above-stated anticorrosion covering is formedby, for example, hot dip plating using such as Zn, Al, Pb, Sn—Fe; orelectroplating using such as Zn, Ni, Cr, Cu, Sn, Au; or electrolessplating using such as Cu, Ni, Sn; or dry coating by physical or chemicaldeposition; flame spraying, etc. The inorganic coating includes such asceramic coating, glassrizing, or enameling. The organic coating includessuch as painting, laminating, or resinrizing. The chemical conversiontreatment includes by such as phosphate treatment, chromate processing,oxidation, and anodic oxidation. In implementation of the presentinvention, it is preferable for maintaining a smooth and even split faceto provide an anticorrosion covering layer of inorganic coating byelectroplating or electroless plating or to form the same by chemicalconversion treatment by chromate processing.

Eighth Embodiment

FIGS. 11A and 11B illustrate a method for manufacturing metal parts withsplit ends joined, the metal parts being obtained by joining a metalplate 1, or a metal rod 2, which is split by the end split method of thepresent invention, to another metal plate 20. FIG. 11A illustrates amethod for joining that is performed with another metal plate 20inserted between the split ends of the metal plate 1, or the split endsof the metal rod 2; FIG. 11B illustrates a method for joining that isperformed inserting split ends of metal plates so that they willinterleave each other.

In this embodiment, the joining of the metal plate 1, or the metal rod2, which has split ends, to another metal plate 20 can be performed byany of pressing (including crimping), welding, fusing, bolting,riveting, and gluing. These methods may be used combining two or moremethod, for example, such as pressing and gluing, bolting and gluing, orriveting and gluing. Joining by gluing is performed in a manner asfollows: Glue is applied between the split ends of the metal plates, orthe split ends of the metal rods, then the glued portions are pressed;in the being pressed state, the glued portions are heated to progresscuring the glue. Or instead, the portions are heated to melt the glueand then cooled to form a uniform glue-applied layer, and then proceedto joining process. The joining may be also implemented in a manner suchthat another metal plate, the surface of which is applied with glue, isinserted between the split ends of the metal plate, or the split ends ofthe metal rod, and then such portion is heated to become bonded.

Usually, it is hard to obtain a joining with adequate quality in joiningbetween dissimilar metal plates. Even though adequate joining quality beobtained initially, the stability thereof is not assured because suchmethod creates very brittle intermetallic compounds at the joininginterface. In the case that the joining between two dissimilar metalplates is made by gluing, a low joining strength is unavoidable due todifference in linear expansion coefficient between the two; thus,ensuring reliable joining has been a major issue. In contrast to this,the strength and reliability of bonding or joining will be largelyimproved when performed in a manner, as illustrated in FIG. 11A:splitting the end part of the metal plate 1, or the metal rod 2,sandwiching another metal plate 20 of dissimilar material between thesplit ends of the metal plate 1, or the metal rod 2, to form athree-layer build-up, and then perform bonding or joining with aconventional method. Further, as FIG. 11B illustrates, a high strengthof bonding or joining can also be obtained by a joining method such thatthe end part of the metal plate 1, or the metal rod 2, made of two kindsof dissimilar metals is split and then such split ends are inserted sothat they will interleave each other; this can improve the reliabilityof the bonding or joining strength.

As stated above, the present invention makes it practicable to split anend part of a metal plate having any of a rectangular, polygonal, orelliptical shape or an end part of a metal rod having a cross-section ofany of a circular, elliptical, rectangular, or polygonal shape. In themultiple press-splitting, it becomes practicable to adjust the length(or depth) of the incision in the splitting freely within the desiredrange by adjusting the position of the clamping device for pinching ametal plate, or a metal rod, in each time of the press-splittingoperation. Further, the end splitting method by present invention iscapable of performing continuously the press-splitting with a slittingpunch or a cleaving punch. This means that the invented method has anexcellent productivity and at the same time offers lowered manufacturingcost. In addition to the above, the metal parts manufactured by the endsplitting method of the present invention is are compatible with notonly changing freely the length of split portion but also adjustment ofsplit thickness freely to a desired thickness. Thereby, it becomespossible to manufacture high-value added metal parts that were hard tomanufacture by the conventional method. Moreover, the metal partsmanufactured by the end splitting method of the present invention isfeasible for employing a new bonding method that was unprecedented.Therefore, the applicability of the present invention to the fields thatrequire more increased thermal resistivity and more enhanced environmentresistance can significantly expand.

The end splitting method, metal parts manufactured by such end splittingmethod, and method for manufacturing such metal parts with split endsjoined by the present invention is are applicable to variety ofapplications such as automobiles, transportation equipment such asrailway equipment such as rolling stocks, electronics devices, machinetools, heavy electrical machinery, nuclear-related equipment, and theleading-edge equipment in the field such as aviation or spacetechnology. Therefore, the usefulness of the present invention isextremely high.

What is claimed is:
 1. A method for manufacturing metal parts with split ends joined, the method comprising: securing a metal plate having any of a rectangular, polygonal, or elliptical shape by pinching both sides thereof with a clamping device, or securing a solid metal rod having a cross-section of any of a circular, elliptical, rectangular, or polygonal shape by pinching at least two opposite-facing portions on the periphery thereof with a clamping device; advancing splitting by pressing a slitting punch or a cleaving punch against a cleft of a split for repeatedly two or more times until a split length reaches a specified extent; inserting another metal plate between the split ends of the metal plate or the metal rod split; and joining both the metals mutually and permanently by a method including any of pressing perpendicular to a splitting direction of the metal plate or the solid metal rod, welding, fusing, bolting, riveting, or gluing, wherein, in advance of each time of each subsequent splitting operation of the two or more times, a position of at least one side of the clamping device that pinches both sides of the metal plate in a prior operation of securing or that pinches at least two opposite-facing portions on a periphery of the solid metal rod in the prior operation of securing, is moved along the metal plate or the solid metal rod in advance by a stroke corresponding to a distance from a position of the cleft of the split toward a distal end of a split desired position, followed by securing of the metal plate by pinching both sides thereof with the clamping device, or by securing of the solid metal rod by pinching at least two opposite-facing portions on the periphery thereof with the clamping device, wherein, in each interval between splitting operations of the two or more times, pressing of the splitting punch or the cleaving punch is suspended, and wherein, on both sides in the case of the splitting punch or on one side in the case of the cleaving punch, a cutting edge is given a tapering shape having at least two taper portions of different angles or curvatures so that the taper portion of the side closer to a tip end of the cutting edge has a smaller inclination angle when measured counterclockwise from a horizontal axis extending perpendicular relative to a longitudinal axis passing through the cutting edge of the splitting punch or the cleaving punch, or a smaller curvature than that of the taper on the side apart from the tip end of the cutting edge.
 2. A method for manufacturing metal parts with split ends joined, the method comprising: determining a desired length of cutting plane in the thickness direction of a metal plate having any of a rectangular, polygonal, or elliptical shape, or in the diameter direction of a solid metal rod having a cross-section of any of a circular, elliptical, rectangular, or polygonal shape; applying a slitting punch or a cleaving punch on the cross-section of the split-desired end of the metal plate, or the metal rod, on a boundary created by the cutting plane; securing the metal plate by pinching both sides of a split-desired portion thereof with a clamping device, or securing the metal rod by pinching at least two opposite-facing portions on the periphery of a split-desired portion thereof with a clamping device; advancing splitting by pressing a slitting punch or a cleaving punch against a cleft of a split for repeatedly two or more times until a split length reaches a specified extent; inserting another metal plate between the split ends of the metal plate or the metal rod split; and joining both the metals mutually and permanently by a method including any of pressing perpendicular to a splitting direction of the metal plate or the solid metal rod, welding, fusing, bolting, riveting, or gluing, wherein, in advance of each time of each subsequent splitting operation of the two or more times, a position of at least one side of the clamping device that pinches both sides of the metal plate in a prior operation of securing or that pinches at least two opposite-facing portions on a periphery of the solid metal rod in the prior operation of securing, is moved along the metal plate or the solid metal rod in advance by a stroke corresponding to a distance from a position of the cleft of the split toward a distal end of a split desired position, followed by securing of the metal plate by pinching both sides thereof with the clamping device, or by securing of the solid metal rod by pinching at least two opposite-facing portions on the periphery thereof with the clamping device; and thereby the metal plate, or the metal rod, is partially split in a longitudinal direction along the cutting plane, wherein, in each interval between splitting operations of the two or more times, pressing of the splitting punch or the cleaving punch is suspended, wherein, on both sides in the case of the splitting punch or on one side in the case of the cleaving punch, a cutting edge is given a tapering shape having at least two taper portions of different angles or curvatures so that the taper portion of the side closer to a tip end of the cutting edge has a smaller inclination angle when measured counterclockwise from a horizontal axis extending perpendicular relative to a longitudinal axis passing through the cutting edge of the splitting punch or the cleaving punch, or a smaller curvature than that of the taper on the side apart from the tip end of the cutting edge.
 3. The method for manufacturing metal parts with split ends joined according to claim 1, wherein the press-splitting is performed by pressing the slitting punch or the cleaving punch against the face of one end of the metal plate, or the solid metal rod, and against the cleft of the split repeating operations of securing the metal plate, or the solid metal rod, using the clamping device after moving either the clamping device on at least one side of the clamping devices or the metal plate, or the metal rod, by a specified stroke in one direction.
 4. The method for manufacturing metal parts with split ends joined according to claim 1, wherein, in the process of splitting the metal plate, or the solid metal rod, longitudinally with respect to the metal plate, or the solid metal rod, by slitting or cleaving and in the process of advancing the splitting by the slitting or cleaving further, the press-splitting by the slitting punch or the cleaving punch is performed with a progressive transfer method comprised of separate processing stages, and wherein, in each time of the press-splitting operation, the position of at least one side of the clamping device that pinches both sides of the metal plate or that pinches at least two opposite-facing portions on the periphery of the solid metal rod is moved in advance by a stroke corresponding to the distance from one end of the metal plate, or the solid metal rod, to the distal end of a split-desired portion.
 5. The method for manufacturing metal parts with split ends joined according to claim 1, wherein a groove cut or a nick line is made in advance on at least one of places in the peripheral portion of the end part of the metal plate, or the solid metal rod, and wherein the places are a place where the slitting punch or the cleaving punch is applied to and a place periphery of the metal plate that corresponds to the split-desired portion of the metal plate, or the solid metal rod.
 6. The method for manufacturing metal parts with split ends joined according to claim 1, wherein the joining of the split ends of the metal plate, or the split ends of the metal rod, and another metal plate is a joining between dissimilar metals.
 7. The method for manufacturing metal parts with split ends joined according to claim 2, wherein the press-splitting is performed by pressing the slitting punch or the cleaving punch against the face of one end of the metal plate, or the solid metal rod, and against the cleft of the split repeating operations of securing the metal plate, or the solid metal rod, using the clamping device after moving either the clamping device on at least one side of the clamping devices or the metal plate, or the solid metal rod, by a specified stroke in one direction.
 8. The method for manufacturing metal parts with split ends joined according to claim 2, wherein, in the process of splitting the metal plate, or the solid metal rod, longitudinally with respect to the metal plate, or the solid metal rod, by slitting or cleaving and in the process of advancing the splitting by the slitting or cleaving further, the press-splitting by the slitting punch or the cleaving punch is performed with a progressive transfer method comprised of separate processing stages, and wherein, in each time of the press-splitting operation, the position of at least one side of the clamping device that pinches both sides of the metal plate or that pinches at least two opposite-facing portions on the periphery of the solid metal rod is moved in advance by a stroke corresponding to the distance from one end of the metal plate, or the solid metal rod, to the distal end of a split-desired portion.
 9. The method for manufacturing metal parts with split ends joined according to claim 2, wherein a groove cut or a nick line is made in advance on at least one of places in the peripheral portion of the end part of the metal plate, or the solid metal rod, and wherein the places are a place where the slitting punch or the cleaving punch is applied to and a place periphery of the metal plate that corresponds to the split-desired portion of the metal plate, or the solid metal rod.
 10. The method for manufacturing metal parts with split ends joined according to claim 2, wherein the joining of the split ends of the metal plate, or the split ends of the metal rod, and another metal plate is a joining between dissimilar metals. 